Literature on test case litigation has led researchers to expect that familiarity with case facts may increase a lawyer's likelihood of victory before the U.S. Supreme Court. However, this question has not been examined empirically. Here, I consider this question. I use data on all federal cases orally argued before the Court during its 2000-2004 terms. I find that interest group lawyers are the only kind of attorneys that are significantly more likely to become involved in the courts of appeals. Early involvement, however, does not affect the probability that a party will win before the Supreme Court
